ORACLE分页方法
1、rownum是oracle系统顺序分配为从查询返回的行的编号，返回的第一行分配的是1，第二行是2，依此类推，这个伪字段可以用于限制查询返回的总行数。
2、rownum不能以任何基表的名称作为前缀。
--自定义表phone
Name Type Nullable
----- ------------ --------
ID NUMBER
NAME VARCHAR2(20) Y
PHONE VARCHAR2(20) Y
ZIP NUMBER Y
--插入数据
ID NAME PHONE ZIP
---------- -------------------- -------------------- ----------
1 e
2 c 101
3 a 102
4 o 103
5 f 103
6 z 103
7 p 103
8 m 104
9 g 102
--显示所有记录,按zip和name排序
select rownum, p.zip, p.name from phone p order by zip, name;
ROWNUM ZIP NAME ROWID
---------- ---------- -------------------- ------------------
2 101 c AAAH3vAABAAAPD6AAB
3 102 a AAAH3vAABAAAPD6AAC
9 102 g AAAH3vAABAAAPD6AAI
5 103 f AAAH3vAABAAAPD6AAE
4 103 o AAAH3vAABAAAPD6AAD
7 103 p AAAH3vAABAAAPD6AAG
6 103 z AAAH3vAABAAAPD6AAF
8 104 m AAAH3vAABAAAPD6AAH
1 e AAAH3vAABAAAPD6AAA
可见,rownum由系统按照记录入库时的顺序排的号,不可以改变,rowid也是的,如果要重排rownum,需要这样...
--按zip和name排序后,显示前5条记录(对照上面的结果),外层的rownum重排了,是我们需要的顺序
select rownum, p.*
from (select zip, name from phone group by zip, name) p
where rownum <= 5;
或者...
select rownum, p.*
from (select t.zip, t.name from phone t order by t.zip, t.name) p
where rownum <= 5;
ROWNUM ZIP NAME
---------- ---------- --------------------
1 101 c
2 102 a
3 102 g
4 103 f
5 103 o
--按zip和name排序后,显示第5-第9条记录(对照上上面的结果)
select *
from (select rownum row_id, p.*
from (select zip, name from phone group by zip, name) p)
where row_id between 5 and 9;
ROW_ID ZIP NAME
---------- ---------- --------------------
5 103 o
6 103 p
7 103 z
8 104 m
9 e